The statements in this section merely provide background information related to the present disclosure and may not constitute prior art.
Internal combustion engines may include engine control systems that deactivate cylinders under specific low load operating conditions. For example, an eight cylinder engine may be operated using four cylinders to improve fuel economy by reducing pumping losses. This process is generally referred to as active fuel management (AFM). Operation using all of the engine cylinders is referred to as an “activated” mode. Conversely, operation using less than all of the cylinders of the engine (i.e. one or more cylinders are not active) is referred to as a “deactivated” mode.
In the deactivated mode, there are fewer firing cylinders. As a result, there is less drive torque available to drive the vehicle driveline and accessories (e.g., an alternator, coolant pump, and A/C compressor). However, the active cylinders operate at a higher efficiency due to reduced pumping losses and achieve better thermal and mechanical efficiency.
A lifter oil manifold assembly (LOMA) is implemented to activate and deactivate selected cylinders of the engine. The LOMA includes electrically operated solenoid valves associated with respective cylinders. The solenoids are selectively energized to enable hydraulic fluid flow to the lifters to inhibit valve lifter operation, thereby deactivating the corresponding cylinders.